Optimize _get_translated_model() when prefetched data has no result.
Optimize _get_translated_model() when prefetched data has no result.

If the object is not found in the prefetched data, there is no point in
checking memcached or perform a single query afterwards. Directly jump
to trying the fallback language.

edoburu/django-parler,zhangguiyu/django-parler,imposeren/django-parler,HiddenData/django-parler,django-parler/django-parler,django-parler/django-parler,HiddenData/django-parler,imposeren/django-parler,zhangguiyu/django-parler,jrief/django-parler,edoburu/django-parler,defivelo/django-parler,ellmetha/django-parler,defivelo/django-parler,skirsdeda/django-parler,jrief/django-parler,ellmetha/django-parler,skirsdeda/django-parler